Many materials, including many commodities, are collected from numerous sources and transported to a central location or facility that may provide temporary storage before transport to another location, or that may process the material directly. Such materials include, for example, grain, grain products, animal feed, sugar, coffee, milk powders, salt, mineral ores, precious ores, and coal products, to name but a few. These materials are commonly referred to as bulk materials, or bulks, and are transported from the sources using any of a number of transport methods, such as, for example, trucks, wagons, rail cars, and ships. Whatever the method of transport, the amount of material that may be transported in a vehicle is generally referred to as a load.
Commingled storage of both liquid and non-liquid bulks is practiced worldwide because the materials are generally considered homogeneous and storage in large holding containers is in many instances the most economical method. As will be recognized, liquid bulk materials mix together when they are commingled, resulting in a liquid mixture that is generally homogeneous, and thus such bulks are generally assumed to be homogeneous. However it is not valid to assume homogeneity for non-liquid or so called dry bulks. Such dry type granular and powder bulks actually layer when added into storage. Also, the non-liquid aspect of granular bulk materials effectively prevents the self-leveling and mixing that is typically seen when storing or transporting liquid bulks. With no self-leveling, stored dry bulks also develop complex surface shapes which make accurate inventory measurement difficult.
FIG. 1 depicts a typical bulk handling facility and process. Here the practice is shown where loads of the bulk are added and stored together at the storage container and shows how bulks are typically withdrawn from the containers. The inbound and outbound diagrams depict the limits of knowledge according to current art regarding the disposition of multiple individual bulk loads stored in any particular container: this disposition is either 1.) unknown (black shading) with only a rough level measurement to indicate gross fill level or 2.) it is unknown with only an undifferentiated cross section (using state of the art surface mapping technology) available to indicate the exact fill level.
As mentioned above, the bulk material in such a facility may originate from numerous different sources, such as individual farms, separate batches or lots, or different mines. Once bulk material is commingled at bulk handling facilities, it becomes increasingly difficult to determine the source of the material. For example, one bin may receive fifty truckloads of material from fifty different sources. When material is removed from the bin, the source of the material is not generally known beyond being from among the total number of sources that were associated with each load added to the bin.
Also, at present it is generally assumed that all of the material properties, such as bulk density, for example, within the storage container or pile is homogeneous or an average of all loads previously added. Such material properties are commonly utilized when attempting to withdraw material from one or more storage containers with the intent of meeting a particular set of final load specifications. For example, an entity may desire to generate a load having a specified material property target by blending material from two storage containers with the material from the first container having a material property that exceeds the specified property target, and the material from the second container having a material property that is below the specified property target. In such a manner, the combined final load may have a higher monetary value as compared to the value of the material from the containers would have individually. However, in many instances such an assumption is erroneous because the inventory stored inside the container is actually made up of multiple layered strata of material with varying material properties (i.e. moisture content, protein content, sulfur content etc.). In the absence of a better method, batch plans are estimated for the final load from the averages data. During load-out, the accumulating batch is continuously sampled to check the actual content versus the intended content to meet the specification. Furthermore, the load-out rates/quantities are adjusted at the source discharge point with the intent of trying to adjust the blend to meet the intended specification. When the required specification is not met, the operator either attempts to re-blend to meet the specification or pays a penalty to his downstream customer (if allowed) for deviation from the specification. Blending is currently considered somewhat of an art form requiring experienced operators.